This invention relates in general to an improved structure for a hybrid multifunctional posterior interspinous fusion device.
An interspinous stabilization device is a device that is adapted to be secured to two or more adjacent vertebrae of a spine in order to stabilize the relative positioning therebetween. An interspinous stabilization device can also be used to facilitate the placement of a bone-growth material, such as a bone graft material, between such adjacent vertebrae to enhance bone growth and promote fusion of the adjacent vertebrae.
Wolff's law of dynamic osteosynthesis states that every change in the function of a bone is followed by definitive changes in its internal architecture and secondary alterations in its external confirmation. This means that osseous tissues remodel in direct response to the stresses placed upon them. Although known interspinous stabilization devices have functioned satisfactorily for stabilizing the relative positioning of the adjacent vertebrae to which they are connected, they are not well suited for desirably maintaining axial compression on a bone graft material that is disposed between such adjacent vertebrae after graft settling occurs, such as described in Wolff's law. Thus, it would be desirable to provide an improved structure for an interspinous stabilization device that more evenly distributes loads throughout the adjacent vertebrae than known structures, and further readily compensates for graft settling so as to maintain continued axial loading of the graft.